/**
 *    Copyright (c) 2019 CK.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package com.github.fartherp.shiro;

import java.io.Serializable;

/**
 * <pre>
 * 实际 {@link org.apache.shiro.subject.PrincipalCollection#getPrimaryPrincipal()} 需要实现的接口.
 * 给出存在redis里唯一数据信息，如：mysql中主键.
 * </pre>
 *
 * @author CK
 * @date 2019/7/15
 */
public interface ShiroFieldAccess extends Cloneable, Serializable {

	/**
	 * get unique value
	 *
	 * @return unique value
	 */
	String unique();
}
